Type-check node.js (#486)

src/parser/node.js

@@ -1,13 +1,16 @@
+// @flow
+
 import Parser from "./index";
 import UtilParser from "./util";
 import { SourceLocation, type Position } from "../util/location";
+import type { Comment, Node as NodeType, NodeBase } from "../types";
 
 // Start an AST node, attaching a start offset.
 
 const commentKeys = ["leadingComments", "trailingComments", "innerComments"];
 
-class Node {
-  constructor(parser?: Parser, pos?: number, loc?: Position) {
+class Node implements NodeBase {
+  constructor(parser: Parser, pos: number, loc: Position) {
     this.type = "";
     this.start = pos;
     this.end = 0;
@@ -17,15 +20,22 @@ class Node {
   }
 
   type: string;
-  start: ?number;
+  start: number;
   end: number;
   loc: SourceLocation;
+  range: [number, number];
+  leadingComments: ?Array<Comment>;
+  trailingComments: ?Array<Comment>;
+  innerComments: ?Array<Comment>;
+  extra: { [key: string]: any };
 
-  __clone(): Node {
-    const node2 = new Node;
+  __clone(): this {
+    // $FlowIgnore
+    const node2: any = new Node;
     for (const key in this) {
       // Do not clone comments that are already attached to the node
       if (commentKeys.indexOf(key) < 0) {
+        // $FlowIgnore
         node2[key] = this[key];
       }
     }
@@ -35,23 +45,25 @@ class Node {
 }
 
 export class NodeUtils extends UtilParser {
-  startNode() {
+  startNode<T : NodeType>(): T {
+    // $FlowIgnore
     return new Node(this, this.state.start, this.state.startLoc);
   }
 
-  startNodeAt(pos, loc) {
+  startNodeAt<T : NodeType>(pos: number, loc: Position): T {
+    // $FlowIgnore
     return new Node(this, pos, loc);
   }
 
   // Finish an AST node, adding `type` and `end` properties.
 
-  finishNode(node, type) {
+  finishNode<T : NodeType>(node: T, type: string): T {
     return this.finishNodeAt(node, type, this.state.lastTokEnd, this.state.lastTokEndLoc);
   }
 
   // Finish node at given position
 
-  finishNodeAt(node, type, pos, loc) {
+  finishNodeAt<T : NodeType>(node: T, type: string, pos: number, loc: Position): T {
     node.type = type;
     node.end = pos;
     node.loc.end = loc;
@@ -63,11 +75,9 @@ export class NodeUtils extends UtilParser {
   /**
    * Reset the start location of node to the start location of locationNode
    */
-  resetStartLocationFromNode(node, locationNode) {
+  resetStartLocationFromNode(node: NodeBase, locationNode: NodeBase): void {
     node.start = locationNode.start;
     node.loc.start = locationNode.loc.start;
     if (this.options.ranges) node.range[0] = locationNode.range[0];
-
-    return node;
   }
 }